Industry News

1. Pump components:

It will cause the transmission parts of the pump, such as the plunger and cylinder bore in the plunger pump, the blades and vane grooves of the vane pump, the gears and shells of the gear pump, and other parts of the pump to wear or freeze, so that the action will fail;

2. Valve components:

It will block the throttle hole and damping hole, and make the performance of the valve deteriorate;

3. Hydraulic cylinder:

Contaminant particles will accelerate the wear of seals and increase the amount of leakage;

During the use of oil, foreign substances will be generated due to pressure, friction, environment and other reasons, and these foreign substances will be used as catalysts to trigger the oxidation of oil products, forming free substances insoluble in oil, causing oil pollution.With the increase of pollution, the viscosity and acidity change, the moisture increases, and the color of the oil changes, which induces the failure of the equipment, resulting in the replacement of the oil.

The residual polluted oil in the equipment circulation system is mixed with the new oil, which plays an oxidative catalytic role, which will accelerate the pollution rate of the oil and reduce the service time of the new oil.Therefore, in order to prevent oil contamination and prolong the service life of oil, it is necessary to quickly remove the pollutants and oxides formed in the oil.

Case: Mode and cause of servo valve failure in hydraulic servo system

1. Failure mode of servo valve:

Main valve erosion failure: When a large number of tiny solid particles in the oil flow through the valve port with the high-speed oil, the throttle edge on the valve core and valve sleeve is eroded, resulting in the blunt edge of the throttle, resulting in the change of the zero zone characteristics of the servo valve, the decrease of pressure gain, and the increase of zero leakage.

Siltation failure of the main valve: particles not greater than the radius gap are gathered in the annular gap between the valve core and the valve sleeve, resulting in the accelerated wear of the valve core and the valve sleeve, the increase of starting friction, the increase of hysteresis ring, the increase of response time, the deterioration of working stability, and the phenomenon of jamming in serious cases.

Main valve jamming failure: The uneven siltation in the annular gap between the spool and the valve sleeve forms a lateral force that causes the metal surface of the valve core and the valve sleeve to come into contact, resulting in microscopic adhesion (cold pressure contact) and seizure. The clamping increases the starting friction, resulting in the unstable operation of the valve, and the jamming failure will be caused when the clamping is serious.

Main valve abrasion failure: Sulfuric acid or hydrochloric acid is produced by the moisture in the oil and the sulfur in the oil additives or the residual chlorine in the cleaning of the parts, resulting in the corrosion of the throttle edges, causing the same consequences as erosion.

Pilot valve failure: The filter blockage installed in the servo valve is caused by the erosion and wear of the nozzle, baffle and the ball at the end of the anti-corrosion rod, and the filter blockage reduces the sensitivity and response of the valve, and it is difficult to drive the power slide valve in serious cases.